Future Irrigation Water is Here

Future Irrigation Water is Here

“Most irrigation systems are designed to use water once. This needs to stop now!”

When you turn on a water tap in your home, where does the so called used up water go? Does the water leave the earth? No. It remains in another state looked at in the past as wastewater – basically good for nothing. Now a day’s reclaimed (grey, rain, storm) and reused (sewer) used water is looked at as more valuable than oil. Right now in parts of the world 4lt of gasoline costs less than 4 lt of bottled water. It is less expensive to fill up your car than to fill your body with bottled water.

Water for irrigation is frowned upon as a huge water waster in many parts of the world. This is not new news and when one looks closer at how landscape irrigation is conceptualized, design, installed and maintained it is a wonder that we still have any water for other uses. A former landscape irrigation design build company owner and now a consultant and educator of the trade I speak from my own experiences. I always like to ask the question: If water was not used for irrigation to produce food – what would you eat? For this many agree that irrigation is a necessary evil but the more informed question why it needs to used in the current manner – once through irrigation and then discarded faster then the water can percolate into the soil.

This is the way most irrigation systems currently work – once through and then more input water. Is this really what needs to go on or is there a better way to irrigate? Glad you asked because this brings me right to the heart of this article “Future Irrigation Water”, which by the way with a little change in how we conceptualize watering the next system designed from under the ground up can become the pathway forward to a sustainable, green, approach to irrigation of landscapes at least and on much larger scales for agricultural irrigation. All it takes is a little visionary thinking about – what is a better way to achieve a healthy landscape without having to draw upon thousands of cubic meters of potable water or the more expensive desalinated or reuse water?

Abu Dabi’s environmental initiative, Masdar, is to become the model of future cities. Many visionary thinkers have been brought together over the past few years to conceptualize what a commercially viable, efficient, and reliable city of the future looks like. I would like to be so bold to be able to add to that vision. A vision about how to utilize irrigation waters many times – a concept I have named “Full Circle Water” a book that I am writing on this subject.

In the dessert areas, sand is the norm as the soil we are forced to utilize to grow plants. In a past article I described how we could use ceramic to hold water and slowly release the water to the plants as the soil tension increased allowing the water to be drawn through the ceramic to the plant. Now let’s look deeper – below the landscape into underground storage systems similar to ancient cisterns still in use today in parts of the world. What would Masdar’s water consumption be like if the majority of the water used by the residents and commercial businesses was captured and reused? Now you are asking doesn’t he know that this is what they are planning to do? Yes, of course and like many others that have gone before, the waters will end up being combined and being treated by expensive and energy consuming methods to a point suitable for irrigation. What happens next is the new approach to future water.

Let’s say the buildings at Masdar were designed to sit upon underground cisterns that were an integral part of their foundation. Could this then not serve as a water collection tank to capture the building occupants wasted water – sink, shower, laundry, dishwasher as long as organic soaps have been used (soon to be renamed liquid gold). The sewer water (black water) would need to be treated and could then be used for irrigation if required or utilized for a totally new idea – heat recovery and or cooling to offset the heating and cooling energy demands of thenew city.

If each building was able to provide enough captured water year round then each building could become a standalone with pumping power provided by a solar pump. Would this not align the sites water demand requirements closer to a fully sustainable city helping to meet residential and business environmental objectives through optimizing the use of the Middle East’s and Northern Africa’s existing natural resources? Ok, you say that each building will not provide enough reclaimed water to meet the landscape plants water requirement due to the extreme evapotranspiration (ET) rates (water evaporated from the plants surrounding soil surface and water used to carry nutrients and support cell development giving integral strength as well as most of the water utilized to cool the plant), so now what. Glad you asked.

What if at the planning stage of the new city a visionary thinker had devised a plan where the infrastructure would utilize a linked tank system – again as part of the foundation of the buildings helping to offset some of the additional developmental costs? Now, when one building runs low on water the water can be moved to where it is required through solar pumps. Or, all the tanks could be linked to a central tank where the water is pumped through a high efficiency irrigation system that makes ever drop of water count. Combine this with in ground irrigation water recovery perforated pipes that send excess water (hope we don’t have this) to the tank system. These pipes could also be used to collect rainfall – regardless how infrequent it occurs, and redirect to the tanks for flushing of the spent water or topping up of the tanks – depending upon the tanks water levels. Filtration of once through irrigation water should not be an issue as the water is passing through a natural filtration system that has worked one its own with our help for millions of years. Food for thought or in this case water for thought. If you need assistance drop me a line. If we all do our part we will be able to leave our children a sustainable world.